Can humans see in the dark? The answer is yes and no. Yes, according to a 2013 study, at least 50 percent of the human population may be able to discern the movement of their own hand in absolute darkness. That revelation might help people feel more comfortable in the dark, but most amateur astronomers aren’t trying to see their hand waving in the dark. They are trying to see a faint, fuzzy object in a dimly lit environment. Also, when one is under the stars, there is no absolute darkness. No, we don’t see as well in the dark as many nocturnal animals, but we do see much better in “relative darkness” than most of us imagine.
By the mid-1800s a few scientists were beginning to explore a possible relationship between Earth’s orbital cycles and Earth’s Glacial Epochs and Ice Ages. Their first step was to develop a working model linking Earth’s cyclical orbital changes to corresponding changes in the amount of solar radiation received by earth. Among scientists to begin the exploration before Milutin Milankovitch, three are of special importance for this article: Joseph Adhemar, Urbain Le Verrier and James Croll. In fact, the Milankovitch cycles are sometimes referred to as the Croll-Milankovitch cycles.
We've already started on the 2018 calendar, and we're looking for your help. As is traditional, we are looking for your great astrophotos, so, please keep an eye out for the URL to where you can submit them, which should be available shortly. Also, as this next year is the 30th anniversary of the club, we would also like your help in providing any historical images you might have. If you have photos from the past 30 years of group gatherings, special events, star parties, or even just pictures of club members showing off the stylish fashions of the day, we would be interested to see and possibly use them in the calendar and other publications over the course of next year. For more information contact our Calendar Manager, David Novotny.
At our last General meeting, we put one of our 10-inch Dobsonians on the auction block. Although we got no acceptable bids, please take this as a signal of things to come – Some aspects of our collection are going to change soon. Examination of our loans over the past year and more indicate changing demands. We have somewhat fewer loans of those large Dobs, and more demand for other kinds of equipment. Some of the changes are due to increased visibility for the whole collection, but other shifts indicate that our members want to try other kinds of equipment.
We have a busy July coming up. RCA welcomes Leo Cavagnaro from Argentina, past president and founding member of our sister club GAMA (Grupo de Astrónomos Mendocinos Aficionados) arriving today, July 1, to spend the next three months with his friends in the U.S. and Portland. He’ll be joined later by our good friend Carlos Guttierez and the current president of GAMA, Elias Juri. They will all be at the Oregon Star Party and several RCA events. Leo will post announcements regarding their stay on the Forum. Please watch for them and give them a warm Oregon greeting when you see them.
The Telescope Library has become much more active this year, meeting growing demand with an expanding group of volunteers. The number of loans is already over twice that of last years' peak, and demand continues to grow. At this writing, we have 36 reservations, some of which stretch into October. Interest in Astronomy is also rising, due to the Eclipse on August 21, and we have seen the effects of this in some reservations and questions. More about this next month.
The morning of July 11, 1991 our family packed up into the car and headed down the road to find a clear spot from which to view one of the longest total eclipses of the sun. It was on a rural road on the big island of Hawaii and fortunately there was little traffic. After fitting everyone with solar viewing glasses and setting up my tripod holding both my still camera and video camera, the partial eclipse was well under way. However, more clouds were starting to move in from the direction of the centerline path of the eclipse. I panicked and with difficulty herded grumpy kids and all back into the car and drove further down the road to get away from the clouds.
Good weather means star parties and with star parties comes the issue of good light management, so it never hurts to review basic field manners. Stargazers do try valiantly to manage their red lights, but LED manufacturers are making their lights brighter and brighter. Given that with modern technology more is always better, we can assume that these lights are going to continue to get even brighter. I did a check for “dimmable red LED flashlight” on Google and came up with these items: Mini Strong Brightness, Energizer Industrial LED, Military Tactical LED, Bulbrite, Brite LED Headlamp... you get the picture. However, a much better choice would be one of the many dimmable astronomical flashlights that are available. We recommend the Rigel Systems Starlight.